The present invention relates generally to solid state memory devices, and more specifically, to performance evaluation of solid state memory devices.
Solid state memory devices are often characterized by complex operating characteristics that may radically affect the performance of the devices. For example, the difference in performance between two solid state memory devices that are accessed in a similar manner is substantially impacted upon the write history of the devices. Accordingly, in order to perform comparable performance evaluations of solid state memory devices, the devices must be preconditioned to ensure that the states of the devices are the same.
One of the challenges with extracting performance data from solid state memory device, such as flash devices, is the amount of time required to precondition a device before performing testing on the device. Solid state memory devices have a set of access restrictions that employ features such as wear leveling to evenly utilize and wear solid state memory devices over time. The introduction of the wear leveling style algorithms requires the solid state memory device to utilize a mapping table to keep track of both the physical and the logical location of stored data. As the solid state memory device is written to, the mapping table is updated to keep track of where the new logical data is stored in the solid state memory device based on the available free blocks in the solid state memory device.
To obtain a performance measurement for a specific workload for a solid state memory device, it takes time to stabilize the mapping table of the device to get the device in the proper state, which may take hours to complete. Furthermore, as more workloads are generated for the solid state memory device, the performance results for the new workload are highly dependent on the previous activity to the device due to the preconditioning effect. This makes replication of performance results from test to test very difficult to without adequate preconditioning time and it also causes performance tests to last for days to weeks.